Chief Mountain Border Crossing is a seasonal checkpoint linking Babb, Montana, with Pincher Creek, Alberta, and the only road crossing within Waterton-Glacier International Peace Park. Proposed by 1915 as a shorter route between Waterton Lakes and Glacier national parks, it was developed during the Great Depression through Canadian relief camps and road construction on the U.S. side from 1934 to 1936. The crossing opened in June 1936 after the customs site was relocated to avoid a steep approach. Early travel was often difficult on the unpaved road, and permanent customs buildings followed later. It remains notable for its scenic setting and winter closure.